This invention relates to a method for the fabrication of concrete blocks or concrete slabs of various formats and sizes, fabrication taking place on the basis of vibrational compaction in concrete-filled molds and dies corresponding to the block or slab surface, the concrete blocks or concrete slabs being subjected to at least one post-forming treatment and subsequently curing.
A method for the manufacturing and/or treatment of concrete blocks is disclosed in European patent document 0319972B1 issued Dec. 8, 1988 to Metten Produktions and Handels GmbH, in which the dies have projections or recesses by which the surface of the concrete blocks is roughened. The dies can, however, also be purposely kept smaller than the molds, resulting in marginal flashes, the removal of which likewise brings about a roughening of the rim of the concrete blocks. The roughening is further increased by virtue of the fact that the surfaces of the concrete blocks are treated with stiff brushes or with compressed air, water, or suitable blasting material, which issues from nozzles.
The concrete blocks manufactured according to this previous method have utility but have a rather rough surface, even the concrete grains adhering to the surface only through the binding action of the concrete.
It is an object of the present invention to provide a method by which a differently formed surface, a wider variety of colors and an enhanced reinforcement of the concrete grains on the surface is achieved. Furthermore, a surface is produced which is reduced in roughness relative to prior concrete block surfaces.
The object of the invention is achieved by virtue of the fact that, as a post-forming measure, the surfaces of the concrete blocks or concrete slabs are treated with soft materials. The soft materials and/or the concrete blocks or concrete slabs are preferably wet or wetted during the treatment operation. This xe2x80x9cwobblingxe2x80x9d treatment of the concrete blocks and concrete slabs in the not yet cured condition and, as appropriate, the presence of liquid during the operation, produces a surface that does experience some roughening but is such that no sharp-edged concrete graining arises.
Soft material stands are combined in one or a plurality of rows and/or fastened to surfaces or disks. They are guided over the surface of the concrete blocks or concrete slabs in arbitrary directions of motion, preferably in oscillatory or rotatory fashion, also as applicable with superimposition of a plurality of rotatory or oscillatory motions. The soft material is preferably made of natural or synthetic material such as cloths, sponges, nonwoven materials, felt, rubber or plastic, which can also be made in strip form and arranged in brush fashion or broom fashion in the rows and on the surfaces or disks.
Before the treatment of the surfaces, the soft material in the form of cloths, sponges and the like can be dipped into water, latexes, colors or color mixtures and then guided over the surfaces of the concrete blocks or concrete slabs, which are arranged on a production pallet. The latexes can also be latex paints, so that a surface coloration is effected in this way or with the colors or color mixtures, independently of the base color of the concrete blocks, which surface coloration experiences a color nuancing by virtue of the fact that the materials of the surfaces normally do not absorb the color uniformly.
Instead of the dipping of the soft substances, such as cloths and the like, however, water, latexes, colors or color mixtures can also be inlet onto the surfaces, preferably sprayed thereon, during the treatment.
An additional color effect can further be achieved by various tinting of the surfaces of the concrete blocks or concrete slabs and through the treatment of the whole production pallet with the soft substances and, as applicable, colors, the colors being distributed over a plurality of block surfaces or slab surfaces.
According to the invention it is also possible, as a further or an additional treatment measure, to apply latex, latex paint and/or colors and/or lacquers, as well as colorless lacquers, to the surfaces of the concrete blocks or concrete slabs before and/or after curing. A visual enhancement of the surface is achieved in this way, absorption of dirt is reduced, and the concrete grains are additionally immobilized. It has been found that the adhesion of dirt or dirt particles is also reduced. For example, chewing gum residues and the like do not adhere to the block surface. The colorfastness is also improved.
Furthermore, it is possible with this method to texture the surfaces of the concrete blocks or concrete slabs upon compaction and lifting of the dies by texturing of the dies, in particular with projections or recesses. The dies can also be purposely kept smaller than the molds so that a rim results. This as well as the roughening is equalized and made uniform by the subsequent xe2x80x9cwobbling,xe2x80x9d so that a particular surface form is achieved.
The method of this invention yields a concrete block or a concrete slab whose surface is textured in a particular way and in which a variegated and/or lustrous surface is formed through special coloring and the concrete grains are immobilized.